Advertising is a form of marketing communication generally used to persuade an audience to partake in a transaction. Commercial ads often seek to generate increased consumption of a company's products or services through “branding”, which involves associating a product or company name or image with certain qualities in the minds of consumers.
Any place an “identified” sponsor pays to deliver their message through a medium is advertising. Virtually any medium can be used for advertising. Commercial advertising media can include wall paintings, billboards, street furniture components, printed flyers and rack cards, radio, cinema and television adverts, web banners, mobile telephone screens, shopping carts, web popups, skywriting, bus stop benches, human billboards and forehead advertising, magazines, newspapers, town criers, sides of buses, banners attached to or sides of airplanes, in-flight advertisements on seatback tray tables or overhead storage bins, taxicab doors, roof mounts and passenger screens, musical stage shows, subway platforms and trains, elastic bands on disposable diapers, doors of bathroom stalls, stickers on apples in supermarkets, shopping cart handles, the opening section of streaming audio and video, posters, and the backs of event tickets and supermarket receipts.
On the spectrum between virtual reality, which creates immersive, computer-generated environments, and the real world, augmented reality is closer to the real world. Augmented reality (AR) refers to the addition of a computer-assisted contextual layer of information over the real world, creating a reality that is enhanced or augmented. The basic idea of augmented reality is to superimpose information in the form of data, graphics, audio and other sensory enhancements (haptic feedback and smell) over a real-world environment as it exists in real time. While augmented reality has been in existence for almost three decades, it has only been in the last few years that the technology has become fast enough and affordable enough for the general population to access. Both video games and cell phones are driving the development of augmented reality. Everyone from tourists, to soldiers, to someone looking for the closest subway stop can now benefit from the ability to place computer-generated information and graphics in their field of vision.
Augmented reality systems use video cameras and other sensor modalities to reconstruct a mixed world that is part real and part virtual. Augmented Reality applications blend virtual images generated by a computer with a real image (for example taken from a camera) viewed by a user.
There are primarily two types of Augmented Reality implementations, namely Marker-based and Markerless:                Marker-based implementation utilizes some type of image such as a QR/2D code to produce a result when it is sensed by a reader, typically a camera on a mobile device e.g. a Smartphone        Markerless AR is often more reliant on the sensors in the device being used such as the GPS location, velocity meter, etc. It may also be referred to as Location-based or Position-based AR.        
While Markerless Augmented Reality is emerging, many markerless AR applications require the use of a built-in GPS to access content tied to a physical location thus superimposing location-based virtual images over the real-world camera feed. Although these capabilities can allow a user to approach a physical location, see digital content in the digital airspace associated with that physical location, and engage with the digital content; such technologies have serious limitations as built-in GPS devices have limited accuracy, cannot work indoors or underground, and may require that a user be connected to a network via Wi-Fi or 4G.
Many AR applications require specialized equipment for example Google Glasses or other head-mounted displays. Although head-mounted displays, or HMDs, have been around for awhile, they are making a comeback as computing devices shrink in size and have better displays and battery life. But this means that the user has to acquire yet another device. This creates a barrier for the creation and presentation of ads to a common user to engage in an Augmented Reality space.
Augmented Reality is an emerging technology and there are limitless potentials but, as noted above, existing implementations have inherent limitations.